Lung cancer results in more deaths in the United States than any other cancer; in fact, it accounts for more deaths than breast, cervix, colon, and prostate cancer combined. About 173,000 people in the United States are diagnosed with lung cancer each year and about 164,000 die each year-that's almost 95%.

The short answer to that question is that lung cancer is an abnormal growth of cells in the lungs, that may eventually spread to the rest of the body if not discovered and treated early. For a more detailed explanation, read our Lung Cancer Overview.

The most significant cause of lung cancer is cigarette smoke. Other possible causes include environmental exposure to asbestos, uranium, or other carcinogens, or genetics. Read more about lung cancer risk factors.

Lung cancer can have a variety of symptoms including coughing or wheezing, shortness of breath, recurring respiratory infections, and more. It is important to remember that symptoms rarely occur until the later stage of lung cancer, when cure is far less likely. For more information, visit Symptoms of Lung Cancer.

You are at risk if you are or have ever been a smoker. The risk increases with age, and with how much you have smoked in your lifetime. Other risk factors include exposure to environmental carcinogens, such as asbestos, or lung scarring.

The I-ELCAP research has focused on patients at a high risk for lung cancer. Several factors contribute to lung cancer risk: age; smoking history; environmental exposure to carcinogens like asbestos, beryllium, uranium, or radon; and exposure to secondhand smoke. The older you are and the more you've smoked or been exposed to smoke and other carcinogens, the higher your risk will be.

There are a number of tests that can be used to detect lung cancer; however, most tests miss many early cancers, and are often ordered only after the patient has started having symptoms. Traditional lung cancer tests include chest x-ray, sputum cytology (analyzing cells in mucus), and bronchoscopy (using a tube through the nose to look at the lungs with a tiny camera).

Based on our research, we recommend using CT scans to screen people at risk of developing lung cancer. CT scans can find very small, early lung cancers, which gives doctors a much better chance of curing them.

Because lung cancer has no symptoms in its early stages, more than 85 percent of the men and women who are diagnosed with lung cancer today are diagnosed in a late stage, after symptoms occur and when there is very little chance of cure. As a result, approximately 95% of the 173,000 people diagnosed each year die from the disease.

With early detection, 85 percent of cancers can be found in the earliest, most curable stage. If treated promptly with surgery, the cure rate is estimated to be 92%(New England Journal of Medicine 2006: 355: 1763-1771).

The latest research from I-ELCAP shows that patients diagnosed with lung cancer as a result of annual CT screening have an estimated cure rate of 80%, regardless of stage and type of treatment.

It is already well-known that small, early-stage lung cancers are much more curable than those found in later stages. Work by other researchers has reported cure rates of 90% or more for small, early-stage lung cancers.